August 7, 2013

Where have all the mosquitoes gone?


For the first time since he began managing the Beachcomber Campground on Ocracoke, Sean Death has had to ask his employees to dust the bug spray bottles on the still-full shelves.

“Last year at this time I was on my fourth or fifth order of bug spray,” he said, “but this year I’ve only ordered once. My display is still full.”

Not that anyone’s complaining, but it’s a curious thing that since the summer began, mosquitoes on Ocracoke are not swarming as soon as you go outside.  Yes, there are some, but dramatically fewer than in recent memory.

“The campers are enjoying our outdoor Friday and Saturday night concerts here (without mosquitoes),” he said.

There even have been dramatic mosquito reductions on Portsmouth Island, noted Rudy Austin, who takes visitors to that island, and on mainland Hyde County.

“I stay in the Ponzer area and there’s nowhere near the numbers of mosquitoes we usually see,” noted Wesley Smith, Hyde County Health Director.

Even the NPS campground on Ocracoke, notorious for lots of mosquitoes, reports a relative lack of the pests.

“It’s really not bad,” said Sarah Richardson, a ranger at the campground office. “I’ve had one bite this year.  I was here last year and it was much worse last year.”

The “no-see-ums,” however, are the main biting pests campers have reported.

“But campers have been really happy,” she said.

This lack of mosquitoes so far this year is also being noticed in Dare County, where mosquito-spraying trucks are making many fewer trips through neighborhoods than in past summers.

A call about this to the entomology department at North Carolina State University in Raleigh had Emeritus Professor Charles Apperson scratching his head.

“They’re much worse here,” he said about the mosquitoes inland. 

But, he gave a possible explanation -- the mosquito eggs are dormant because of lower than normal tides.

“My guess is you haven’t had the tide conditions for the eggs to hatch,” he said.

He explained that mosquitoes lay their eggs high in the salt grasses and black needle rushes with the expectation that the rising tide will dip them into the water where the eggs will hatch into larvae then pupae then to adult when they emerge and go on their blood-sucking quests. 

The eggs are covered with a waxy substance to withstand dry conditions.  If the tides don’t rise to envelope the eggs, they can stay in the egg stage for several years.
Beaver Tillett, an islander whose job it has been for the last several years to drive the bug-spraying truck, has only been out four times this year.

“Usually by this time I’ve gone 15 times,” he said. “The last time I went was two weeks ago.”

He suggests something else as to the relative lack of mosquitoes. He has been putting larvacide along the sides of village roads — in the “mosquito” ditches and other low spots in the marshes around the village and also some of the drainage areas around village roads.  He also spreads an “adulticide” mosquito chemical around.  He has been doing this for the last three years.  Perhaps the island is seeing the result of this work, he said.

Moreover, the island has not had the weather conditions certain kinds of mosquitoes love. We had a cooler-than-normal spring and fewer days in the 90s this summer.

“On average, we’ve only had nine days above 90 degrees,” he said.

He explained that we’re not seeing as many of the saltwater mosquitoes that show up in April and May.  The mosquitoes people are fending off now are hatched in standing fresh water.
These are the “summertime” mosquitoes, he said, noting that people should strive to not have standing water in containers around their homes and yards.

“These came to the United States from Japan in recycled tires shipped to Georgia 20 years ago,” Tillett said. “Now they’re from the West Coast to Maine.”  These mosquitoes hide in shade during the day and come out at night.

He also said the summer is not over, and the island might not enjoy this mosquito respite for much longer.

“They’re gonna get bad here,” he said.

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